diff --git a/contrib/build-wine/electrum.nsi b/contrib/build-wine/electrum.nsi
index a42a66884..6aa4ce22b 100644
--- a/contrib/build-wine/electrum.nsi
+++ b/contrib/build-wine/electrum.nsi
@@ -87,6 +87,55 @@
 
   !insertmacro MUI_LANGUAGE "English"
 
+;--------------------------------
+;Functions
+
+!macro CreateEnsureNotRunning prefix operation
+
+Function ${prefix}EnsureNotRunning
+  ; pop the directory to check from the stack into $R0
+  Pop $R0
+  ; if the dir at $R0 doesn't exist, jump to nodir
+  IfFileExists "$R0" 0 nodir
+    ; Find all .exe files in the directory, $1 is the handle, $2 is the filename
+    FindFirst $1 $2 "$R0\*.exe"
+    IfErrors noexe 0
+
+    checkloop:
+    ; Skip checking the uninstaller if we are the uninstaller to avoid locking the uninstaller itself
+    !if "${prefix}" == "un."
+        StrCmp $2 "Uninstall.exe" skipfile 0
+    !endif
+
+    ; Check if we can append to the .exe file. If we can't that means it is still running.
+    retryopen:
+    FileOpen $0 "$R0\$2" a
+    IfErrors 0 closeexe
+      MessageBox MB_RETRYCANCEL "Can not ${operation} because $2 is still running. Close it and retry." /SD IDCANCEL IDRETRY retryopen
+      FindClose $1
+      Abort
+    closeexe:
+    FileClose $0
+
+    skipfile:
+    ; Find next .exe file
+    FindNext $1 $2
+    IfErrors done 0
+    Goto checkloop
+
+    done:
+    FindClose $1
+
+  noexe:
+  nodir:
+FunctionEnd
+
+!macroend
+
+; The function has to be created twice, once for the installer and once for the uninstaller
+!insertmacro CreateEnsureNotRunning "" "install"
+!insertmacro CreateEnsureNotRunning "un." "uninstall"
+
 ;--------------------------------
 ;Installer Sections
 
@@ -99,6 +148,14 @@ Function .onInit
 		SetErrorLevel 740 ;ERROR_ELEVATION_REQUIRED
 		Quit
 	${EndIf}
+
+  ; Check if already installed and ensure the process is not running if it is
+  ReadRegStr $R0 HKCU "Software\${PRODUCT_NAME}" ""
+  IfErrors noinstdir 0
+    Push $R0
+    Call EnsureNotRunning
+  noinstdir:
+  ClearErrors
 FunctionEnd
 
 Section
@@ -175,3 +232,9 @@ Section "Uninstall"
   DeleteRegKey HKCU "Software\${PRODUCT_NAME}"
   DeleteRegKey HKCU "${PRODUCT_UNINST_KEY}"
 SectionEnd
+
+Function UN.onInit
+  ; Ensure the process is not running in the uninstallation directory
+  Push $INSTDIR
+  Call un.EnsureNotRunning
+FunctionEnd